A Japanese night view heritage site, an artificial floating island—Umihotaru (海ほたる)

Text & Photography / Chi Bing-Hui

The Japanese are renowned for their strong design capabilities and high execution in architecture, which serve as a global benchmark. Among these, Umihotaru (海ほたる)—a spot less visited by Taiwanese—is an artificial floating island that links the underwater tunnel between Kawasaki and Kisarazu. Though it serves a similar function to a rest area, the vast seascape is absolutely worth a short visit.

“Umihotaru” refers to a type of bioluminescent plankton in the sea that glows at night, resembling fireflies under the ocean. The island is named after this phenomenon. At night, when viewed from afar, it looks like a bright dot floating on the vast ocean, reflecting the city lights behind it. The twinkling lights add a romantic atmosphere, and it has been selected as one of Japan’s Night View Heritage sites.

Umihotaru is hailed as one of Japan’s engineering and technological masterpieces. To the east lies a 4.4-kilometer-long bridge, and to the west, a 9.5-kilometer-long underwater tunnel. From a distance, it resembles a massive, stationary cruise ship. The entire project cost approximately 1.5 trillion yen. Since Chiba Prefecture is a peninsula, separated from Tokyo and Kanagawa Prefectures by Tokyo Bay, traveling between them previously required a long detour. This series of structures was designed to solve that issue, cutting about an hour off the travel time upon completion.